论文标题
天空中的大风筝：Abell 2626中无线电源的Lofar观察
The great Kite in the sky: a LOFAR observation of the radio source in Abell 2626
论文作者
论文摘要
Galaxy群集Abell 2626（也称为风筝）的无线电来源因其独特的形态而闻名，该形态由四个对称弧组成。先前的研究已经在不同的频率及其与周围热等离子体的相互作用探测了该源的性质，但其起源难题仍未解决。我们使用144 MHz的Lofar两米天空调查的新的低频阵列（LOFAR）观察来研究风筝的起源。}我们对新的无线电数据进行了详细分析，并将其与档案无线电和X射线观测结合在一起。我们已经制作了一个新的，已解决的源索引图，分辨率为7 $''$，我们研究了无线电和X射线发射的空间相关性，以研究热和非热等离子体之间的相互作用。新的Lofar数据通过发现了与ARC相连的两个陡峭光谱（$α<-1.5 $）的羽毛，从而改变了我们对风筝的看法。光谱分析首次表明沿弧的光谱的空间趋势具有弯曲的同步子光谱的证据，并且与X射线表面亮度的空间相关性。根据我们的结果，我们建议风筝最初是X形射电星系，其化石无线电等离子体在中央活性银河系核的活性结束后，由于所包含的热等离子体的运动而被压缩。化石等离子体的压缩和对流之间的相互作用与中央星系的核活动的重新启动可以增强化石血浆的无线电发射，从而产生风筝的弧。我们还介绍了在同一领域对水母星系的第一个低频观察，其中我们在较高的频率下检测到没有对应物的延长的低频发射。
The radio source at the center of the galaxy cluster Abell 2626, also known as the Kite, stands out for its unique morphology composed of four, symmetric arcs. Previous studies have probed the properties of this source at different frequencies and its interplay with the surrounding thermal plasma, but the puzzle of its origin is still unsolved. We use new LOw Frequency ARray (LOFAR) observation from the LOFAR Two-meter Sky Survey at 144 MHz to investigate the origin of the Kite.} We present a detailed analysis of the new radio data which we combined with archival radio and X-ray observations. We have produced a new, resolved spectral index map of the source with a resolution of 7$''$ and we studied the spatial correlation of radio and X-ray emission to investigate the interplay between thermal and non-thermal plasma. The new LOFAR data have changed our view of the Kite by discovering two steep-spectrum ($α<-1.5$) plumes of emission connected to the arcs. The spectral analysis shows, for the first time, a spatial trend of the spectrum along the arcs with evidence of curved synchrotron spectra and a spatial correlation with the X-ray surface brightness. On the basis of our results, we propose that the Kite was originally an X-shaped radio galaxy whose fossil radio plasma, after the end of the activity of the central active galactic nucleus, has been compressed due to motions of the thermal plasma in which it is encompassed. The interplay between the compression and advection of the fossil plasma, with the restarting of the nuclear activity of the central galaxy, could have enhanced the radio emission of the fossil plasma producing the arcs of the Kite. We present also the first, low-frequency observation of a jellyfish galaxy in the same field, in which we detect extended, low-frequency emission without a counterpart at higher frequencies.
